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If ""^(n)P(7)=42. ""^(n)P(5). find n....

If `""^(n)P_(7)=42. ""^(n)P_(5).` find n.

Text Solution

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The correct Answer is:
`therefore n=12`
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If ""^(n+1)P_(5):""^(n)P_(6)=2:7 , find n.

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Knowledge Check

  • If ""^(n)P_(5)=""^(n)P_(6) then n is

    A
    15
    B
    7
    C
    6
    D
    10

  • If a,b,c are the values of n where ""^(n)P _(7) = 42 ""^(n)P_(5) ,""^(n)P_(4) = 1680 , ""^(n) P_(3) =1320 respectively then the ascending order of a,b,c is

    A
    a,b,c
    B
    b,c=a
    C
    c=b,a
    D
    c,a,b

  • If ""^(n)P_(r)=""^(n)P_((r+1)) and ""^(n)C_(r) = ""^(n)C_(r-1), then (n,r) =

    A
    `8,9`
    B
    `6,7`
    C
    `4,5`
    D
    `3,2`

    • Similar Questions

    Explore conceptually related problems

    Find the value of n such that ""^(n)P_(5)=42""^(n)P_(3), n gt 4

    If ""^((n+1))P_(5): ""^(n)P_(6)=2:7 , find

    If ""^(n)P_(4)=1680, find n.

    If ""^(n)P_(4)=210 , find n.

    If ""^((n+1))P_(5):""^(n)P_(5)=3:2 then n is

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